Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Draft in moulding

Draft in moulding

Draft in moulding

Got a question here.Going by the definition of the Draft,it is useful for easy removal of the part in the moulding.If we need a straight face in the final part,how do i go with it?Need clarity pls.

RE: Draft in moulding

In original sand molding, the draft angle was needed to remove the forming object from the sand mold. Today's mold forms and some modern forming options offer some ways to minimize the draft angle, but not many. Some of these options are more expensive than sand-formed-by-unskilled-workers-in-low-tech-conditions.

Without more detail of the materials, the tolerances, and the mold itself - we cannot say more. Be aware that your mold company (the casting company) does want to make it simpler for themselves! Not for yourself, or the machining that has to be done to cut the wall perfectly flat later.

RE: Draft in moulding

Hi racookpe,
Thanks for your reply.So i understand that the machining is done after the draft in order to make it a flat surface.Am i right in my understanding?

RE: Draft in moulding

What kind of molding are you talking about? The processes and requirements vary dramatically. In most cases you can get what you want, but the costs can skyrocket.

RE: Draft in moulding

As John2025 mentioned, we need to know the material and process before we can give useful suggestions. A drawing or sketch of the part would be equally helpful.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: Draft in moulding

If the part is injection molded plastic you can use "side pulls". I think they maybe are also used on die cast metal parts. Lot's of money though!

RE: Draft in moulding

Hi folks,
Thanks for your replies.But here i want to understand the process of why the draft is given and if the part needs a flat face (apart from tapered face),then what will be the solution.

RE: Draft in moulding

sudhakarn - look at any book on the casting process. Google "casting draft" or "molding draft"

Presently your question requires millions of answers to maybe figure out what problem you think you have.

RE: Draft in moulding

We cannot even begin to offer you an suggestion unless we know the material and the process. You must understand that sand casting grey iron is a far different process than injection molding glass filled nylon, and thus, requires a different method to accomplish a certain design feature. While there are many extremely knowledgeable technical people on this form, few of us are clairvoyant.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: Draft in moulding

Hi Folks,
Thanks a lot for your replies.I am a new bie for manufacturing.I just want to understand the fact that whether we provide a draft for parts with the straight faces instead of a tapered face.Please excuse me if i am not clear in explaining my requirement. Thanks.

RE: Draft in moulding

On a typical squarish part, it is possible to have zero draft on up to two faces, by adding draft to the complementary faces.

It is also possible to mold faces that are not perpendicular to the mold's parting line.

Read a book or two.

Better, design a part and bring a print to an experienced molder.
(S)he will redline it to death, and you will learn more than we can teach you here.

Mike Halloran
Pembroke Pines, FL, USA

RE: Draft in moulding

If you define a flat face (vertical face), you have defined NO DRAFT.
If you define a face with "draft" that face is IS SLOPED.

Now, as pointed out above, two faces can be parallel to each other and vertical, and - with great care in molding and mold removal - two other faces can be molded with draft.
Or you can define a face with draft (slope) and then machine the face afterwards vertical.

Or you can select a different molding technique than cheap sand casting.

RE: Draft in moulding

Hi Racoop,
Thanks a lot for your insights again.Your replies are more positive and encouraging than many other replies here.

RE: Draft in moulding

"Your replies are more positive and encouraging than many other replies here."


Your statement above is unfair and unacceptable . The members have spent their time and contributed based on your ill prepared and poorly drafted question.

It lacked details and specifics, yet these outstanding and helpful members tried their best to offer suggestions.

In fact,I restrained myself from participating as your question was a lazy one.

My advice to you is come back after framing your questions well and avoid deriding other members who tried to be helpful.

@ All other members who participated in this discussion THANKS.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

RE: Draft in moulding

Hi Arumrao,
Thanks for your insights.Apologies in case i have hurt any one.I just wanted to mention that the users can be polite and gentle in their replies.Because had i been an expert,i would not have posted the question in that level of ignorance.

Hope you understand.Again apologies from my side.Not everyone is an expert in everything.

RE: Draft in moulding

Polite and gentle is provided elsewhere.

Your original question was grossly incomplete, because in it, you did not reveal:
- what material you are trying to mold.
- how big the part is.
- how deep the part is.
- how complex the geometry is.
- how tight the tolerances need be, for each and every feature of the molded product.
- how many parts you need now, and over the design lifetime.
- how many parts you need in a day.
- how much capital you can raise.

The answers to that original question will vary considerably, depending on your answers to the items mentioned hereinabove, and many more.

Mike Halloran
Pembroke Pines, FL, USA

RE: Draft in moulding

Hi Scenery driver,
Thanks a lot.Better late than never.

RE: Draft in moulding

If you need a flat face then very simple that has to be at the top or the bottom of the part as seen sitting in the cope or drag.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


White Paper - The Criticality of the E/E Architecture
Modern vehicles are highly sophisticated systems incorporating electrical, electronic, software and mechanical components. Mechanical systems are giving way to advanced software and electronic devices, driving automakers to innovate and differentiate their vehicles via the electric and electronic (E/E) architecture. As the pace of change accelerates, automotive companies need to evolve their development processes to deliver and maximize the value of these architectures. Download Now
White Paper - Model Based Engineering for Wire Harness Manufacturing
Modern cars, trucks, and other vehicles feature an ever-increasing number of sophisticated electrical and electronic features, placing a larger burden on the wiring harness that enables these new features. As complexity rises, current harness manufacturing methods are struggling to keep pace due to manual data exchanges and the inability to capture tribal knowledge. A model-based wire harness manufacturing engineering flow automates data exchange and captures tribal knowledge through design rules to help harness manufacturers improve harness quality and boost efficiency. Download Now
White Paper - Modeling and Optimizing Wire Harness Costs for Variation Complexity
This paper will focus on the quantification of the complexity related costs in harness variations in order to model them, allowing automated algorithms to optimize for these costs. A number of real world examples will be provided as well. Since no two businesses are alike, it is the aim of this paper to provide the foundational knowledge and methodology so the reader can assess their own business to model how variation complexity costs affect their business. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close